Hi, friends, I am now using a small 3 volt DC motor on my handheld device. Its maximum power is 80mW, current 57mA. The motor is initially powered to spin towards one direction before the power is off. I want it to spin back when the power is lost. How can it be done? Actually i have a design using FETs and Cap to do this. But the spin not strong enough. May i know any friends come across similar senario b4? thx in advance.
Montoya
I came from the automatic door industry (you know, the ones that slide or swing open at an airport, grocery store, hotel, etc.) A sliding door didn't have a spring, so you needed power to open it, and power to close it. A swinging door had a spring, so opening it would need power to distend the spring, and closing it would usually be achieved by letting the spring close it, without power. A braking resistor/potentiometer would be placed across the motor to slow down the closing.
If i remember correctly, we needed a way to close a sliding door if there was a blackout and we lost power. For such a task, we had a battery pack.
So to answer your question, i guess you'd need a spring to let it close if you lost power. Since i ain't a mechanical engineer, I wouldnt know how a spring is put into the motor, i guess thru a gearbox or something.
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